1. Field of the Disclosure
The present disclosure relates to the field packet-switched networks.
2. Description of the Related Art
Packet-switched networks, such as Digital Subscriber Loop (DSL) networks, are used by service providers to provide a variety of services, such as Internet access, Voice over Internet Protocol (VoIP), Internet Protocol Television (IPTV), Video on Demand (VoD), etc. Often, service level agreements (SLAs) are made that specify quality of service (QoS) levels for the various services provided to the customers. The specified QoS levels or the service levels set by the service provider may be different for different services. For example, the QoS level for a voice service, such as VoIP, may be higher than the QoS level for a data service, such as the access to the Internet.
The ability to meet specific QoS level of a service depends upon a number of factors, such as the current load on the network and the capacity and condition of the various network elements, such as servers, routers, switches, the transport links that link the various network elements to the customer premise equipment (CPE). In many situations, the network may not be able to provide the requested services at the selected or desired QoS levels to all customers. If the network is overloaded, the quality of service may fall below an acceptable level for all the customers being serviced by the associated network. In some instances, such an approach may be acceptable for data traffic, such as Internet traffic, where in the long term the QoS levels are met and the effect in the short term can be tolerated, but not for the voice service.
Quality of service mechanisms have been implemented in routers and switches in an effort to provide differentiated services in packet-switched networks. These mechanisms generally operate by differentiating the data packets (“packets”) as they arrive at the router or switch, separating the packets into queues for each type of service, and then servicing each queue with a different priority to provide the desired service at a QoS level. These QoS mechanisms alone do not tend to control or police the access to the network and leave the network susceptible to overloading by a convergence of too many customers. Using a video service as an example, as the number of video service requests grows, even with a queuing scheme on video servers, the routers and switches can be overloaded, thus degrading the QoS level for all of the customers. Thus, there is a need for an efficient system and method for managing the traffic on a network so as to maintain the QoS at selected levels.